Electrical handlamps using incandescent lamps have been known for decades. These lamps have certain disadvantages in that they tend to become very hot during continued use, and most commercially available incandescent lamps are not well-suited to the rugged conditions of use of most handlamps, particularly those used in industrial and commercial applications. If a handlamp with an incandescent lamp is dropped, almost invariably the filament will break and the lamp must be replaced.
Fluorescent handlamps are also known. In one commercial fluorescent handlamp, the ballast is incorporated directly into the electrical power cord which feeds the handlamp, so that there is a longer section of cord between the ballast and the handlamp itself. A shorter section of electrical cord extends between the ballast and the outlet receptacle to which the plug is connected for use.
Although this device provides the advantages of greater efficiency and less heat build up than with incandescent lamps, it is somewhat cumbersome in that the ballast must be dragged around the floor. Further, the ballast, which is not light, must be supported. This limits portability and maneuverability. Finally, this system is difficult to service in the field if it is required to replace the ballast or other component.
There has also been a handlamp in which a ballast is included directly in the handlamp itself. This is an explosion-proof handlamp in which the handle of the lamp is a metal casing; and the ballast is incorporated into the metal handle and securely embedded in a potting compound within the handle. This explosion-proof construction is prohibitively expensive for ordinary commercial and industrial usage, and it is quite heavy, and, thus, not easily maneuvered or hung from a support.
The present invention overcomes these disadvantages and provides a simple and reliable handlamp, yet one which is economical to manufacture and easily serviced in the field without the need for special tools.